Filter element



Nov. 29, 1949 v E, G. sMlTH ET Al." 2,489,682

FILTER ELEMENT Filed March l, 1948 r f Patented Nov. 29, 1949 s FILTER ELEMET Edmund G. Smith, Cedar Grove, and'Otell M; Cocchiarella, Newark, N. J., assignors to Equip. ment Development Co., Inc., Montclair, N. J., a corporation of New Jersey Application March 1, 1948, Serial No. 12,348

9 Claims. (C1. 210-170) This invention relates to filter elements and more particularly to a novel and improved tube construction for filters and thickeners.

An object of the invention is to provide a filter or thickener tube construction in which the filterv cloth is supported in spaced relationship from the tube surface by a novel and improved spacing means which contacts and blocks off a minimum area of ltercloth, is iiexible` and resilient to a degree to conform to the contacting surfaces, is simple to construct and assemble, and which introduces a minimum of resistance to the fiow of liquids.

Another object is to provide a novel and improved means for attaching and supporting the spacing means and the filter cloth.

Another object is to provide a construction wherein an air lock is prevented from forming during the blow-back periods.

Various other objects and advantages will be apparent as the nature of the invention is more fully disclosed.

In accordance with the present invention, the tube lter comprises a tube which is adapted to be immersed in the liquid to be thickened and which carries a backing fabric and a filter fabric, spaced from the tube surface by a suitable spacing means. The filter fabric may be made as set forth in a co-pending application of Edmund G. Smith, Serial No. 706,994, filed October 3l, 1946, for Filter cloth, which describes a cloth woven from a tightly twisted yarn having the property of preventing passage of liquid through the yarn and confining the flow to the spaces between yarns. This construction has the advantage of preventing solid particles from becoming lodged in the yarn from which they are not read ily removed.

In the present construction the filter fabric is backed by a backing fabric which is more openly woven than the filter fabric and serves as a support therefor. The backing fabric is held spaced from the outer tube surface by a coiled wire mesh made from a series of longitudinal strips of coiled Wire with alternate strips being coiled with a right hand and left hand pitch respectively. The strips are generally triangular in section and are interleaved to provide loops in which a. locking rod is inserted to secure the adjacent strips together and form a sheet or layer of such coils. This layer is wrapped around the tube and its ends are secured to a suitable longitudinally extending clamping means carried by the tube. The coils are preferably made of such a. shape that their outer surfaces form substantially a continuous peripheral supportvfor the backing fabric with the opposite points of the coils bearing against the surface of the tube.

Although the novel features which are characteristic of this invention are pointed out more particularly in the claims, the nature of the invention will be better understood by referring to the following description, taken in connection with the accompanying drawings, in which a speciiic embodiment thereof has been set forth for purposes of illustration.

In the drawings:

Fig. 1 is a side elevation of a filter tube embodying the present invention with parts broken away to show the construction thereof;

Fig. 2 is a vertical section taken on the line 2-2 of Fig. 1;

Fig. 3 is a horizontal section taken on the line 3-3 of Fig. 1; and

Fig. 4 is a broken vertical section taken on the line 4-4 of Fig. 3.

Referring to the drawings more in detail, the invention is shown as applied to a vertical tube IIJ which is attached as by welding at its upper end to a horizontal header II which, as shown in Fig. 2, may comprise an open-ended hor-izontal cylinder having sight glasses I2 secured in the two ends thereof by suitable means such as gasket rings I3 and locking rings I4. To the side of the header II is secured a pipe I5 carrying a clamping plate I6 having a pair of notches I'I formed therein to receive clamping screws by which the plate I6 may be clamped to a suitable manifold not shown. The header II is provided with suitable openings I8 and I9 communicating with the tube Ill and the pipe I5 respectively.

The lower end of the tube I0 is closed by a bottom plate 20 which may be welded thereto and is provided with an outwardly extending annular flange 2| to support the spacing coils 28 to be described. At its lower end the tube I0 is provided with a plurality of vertical openings or slots 22. A ring 24 which is coextensive with the fiange 2| is secured to the tube I8 in spaced relation to the ange 2I to engage the tops of the spacing coils 28.

The spacing coils 28 are made by a coiled wire and are generally triangular in section as shown in Fig. 3. Alternate coils are wound with a right hand and left hand pitchl respectively as indicated in Fig. 1 so that they may be interleaved by merely pushing the adjacent coils together. As thus interleaved they form loops which are locked by the insertion of vertical rods 29. In this way a plurality of coils are joined together to form a latticed layer of sufficient extent to be wrapped around the outer surface of the tube as shown in Fig. 3. Clamping rods 30 are inserted in the end coils of the layer and are secured to a vertical block 3| by means of cotter pins 32 having heads which extend around the rods 30 and shanks having heads which extend through holes in the block 3| and ends 33 which are bent over to lock the cotter pins in place.

The coils 28 are preferably so formed that their outer peripheral surfaces are arcuate as indicated at 35 (Fig. 3), so that the succession cf coils forms a substantially continuous peripheral surface adapted to support a substantial area of the backing fabric with the points 36 of the coils bearing against the outer surface of the tube I0. The coils as thus assembled are held against substantial movement by the block 3| and are supported by the flange 2| and ring 24. The block 3| may be attached to the tube I0 by 4suitable means, such as spaced lugs 31 which are welded or otherwise secured to the tube IIJ and to the block 3|.

A backing fabric 40 of comparatively open mesh and a. filter fabric 4| which is of comparatively iine mesh are wrapped around the outer surfaces 35 of the coils 28. The free ends of the backing fabric 48 and the filter fabric 4| are disposed over the block 3| and are clamped thereto by means of a soft gasket 42 which may be made of plastic, rubber or other deformable material and a clamping strip 43 which is attached to the block 3| by a series of bolts 44. The bolts 44 are tightened sufficiently so that the gasket 42 clamps and seals the ends of the fabric layers.

The lower ends of the fabric layers are turned under the flange 2|, as indicated at 48 (Fig. 1) and are clamped against the fiange 2| by means of a clamping plate 49 having an annular insert 50 of soft depressible gasket material. The clamping plate 49 is held in clamping engagement with the turned under ends of the fabric layers by means of a nut 58 on a bolt 5| which is secured in the bottom plate 2 0.

The upper ends of the fabric layers are turned over the ring 24, as indicated at 53, and are clamped against the ring 24 by means of a clamping ring 54 having an annular insert 52 of soft compressible gasket material similar to the gasket material 50, above mentioned- The ring 54 fits loosely around the outer surface of the tube I0 and is held in clamping engagement with the ring 24 by means of a plurality cf clamping nuts 55 which are threaded on bolts 56 rigidly secured as by weding in a ring 5l which in turn is rigidly secured tc the outer surface of the tube l0. The arrangement is such that the clamping nuts 55 may be brought into clamping engagement with the upper surface of the clamping ring 54 to hold the same under suflicient pressure to form a seal with the turned in portions 53 of the fabric layers.

A vent 68 is formed in the tube l0 near the upper portion of the space occupied by the coils 28.

In the operation of this device the tube Ill is immersed in the liquid slurry to be filtered or thickened and the plate I6 is clamped to a suitable manifold so that suction is applied to the interior of the tube I8 for filtering or blow-back liquid may be fed from the manifold to the tube I0 for re'noving the filter cake in a manner well known in the art. When suction is applied to the tube ||l the liquid is drawn through the filter fabric 4| and the backing fabric 40 into the space occupied by the coils 28 wherein the liquid flows downwardly and thence through the openings 22 into the interior of tube I0 and is drawn ofl' therefrom by suction into the manifold. During this portion of the process the arcuate portions of the coils furnish substantial support for the filter fabric 4| at points corresponding to a plurality of closely spaced parallel rings extending the length of the tube. At the same time the filter fabric 4| is spaced from the coil surfaces by means of a backing fabric so that the pores are not completely blocked off even at the points where-the filter fabric overlies the surfaces 35 of the coils. In addition the fabrics are free to move with respect tothe coils so that the same parts of the fabric do not always remain in contact with the surfaces 35 of the coils. As the fabric moves due to the internal pressure produced by the blow-back liquid and due to physical movement of the tube I0 in the external liquid the resilience of the coils 28 and supports allows the coils to be displaced so as to conform to the various positions of the fabric thereon.

For the removal of the filter cake at the end of the filtering cycle suction is removed at the manifold and liquid is forced back through the pipe I0. This liquid flows through the slots 22 at the bottom end of the tube I0 and upwardly around the various coils 28 to equalize the pressure on the inside and outside of the filter fabric, or if desired to apply a pressure differential from the inside to the outside which tends to remove and dislodge the filter cake. Due to the vent 60, all air is removed from the annular space between the fabric and the tube during the suction period. Hence the space may be rapidly and completely filled with liquid as required for the removal of the filter cake.

It is to be noted that in this construction no clamping element with the exception of the strip 43 projects beyond the surface of the filter fabric 4|. Hence there is no element which would interfere with the free removal and dropping of the lter cake from the outer surface of the fabric. The clamping plate 49 is smaller in diameter than the fabric layer for the above reasons.

It will be noted that the fabric is clamped and sealed with respect to the tube by the upper and lower gaskets 50 and 52 and by the longitudinal gasket 42. The fabric may be removed for renewal purposes by loosening the nut 58, nuts and bolts 44. This, however, does not disturb the coils which are held secure by the cotter pins 32. The coils, however, may be readily removed when desired by removing these cotter pins.

Although a specific embodiment of the invention has been shown for purposes of illustration, it is to be understood that various changes and modications may be made therein as will be readily apparent to a person skilled in the art. The invention is only to be restricted in accordance with the scope of the following claims.

What is claimed is:

1. A tube filter comprising a tube adapted to be immersed in the liquid to be filtered, a block extending longitudinally along one side only of said tube and having an outer surface spaced from the surface of said tube, a filter fabric surrounding said tube with side edges overlapping said block, a sealing gasket disposed along said block over said side edges and sealing the overlapped portiens, a clamping strip disposed over said gasket, and members securing said clamping strip to hold said gasket in pressure engagementwith said fabric edges to secure and seal the same.

latticed spacing members disposed between said tube and fabric and extending around said tube to space the fabric therefrom and form an annular liquid receiving chamber, and an opening in the bottom of the tube for the passage of liquid between said chamber and the inside of said tube.

2. A tube filter comprising a tube adapted to be immersed in the liquid to be filtered, a block extending along said tube and having an outer surface spaced from the surface of said tube, a filter fabric surrounding said tube with side edges overlapping said block, a gasket disposed along said block over said side edges, a clamping strip disposed over said gasket, and members securing said clamping strip to hold `said gasket in pressure engagement with said fabric edges to secure and seal the same, latticed spacing members between said tube and fabric to form a liquid receiving chamber, an opening in the'bottom of the tube for the passage of liquid between said chamber and the inside of said tube, rings xed to said tube at the top and bottom of said fabric over which the top and bottom edges of the fabric are folded, clamping rings including gaskets engaging said folded over fabric to clamp the same against said fixed rings, and adjustable screw means to hold said clamping rings in pressure engagement with' said fabric for securing and sealing the top and bottom edges thereof.

3. A tube filter, as set forth in claim 2, in which said spacing members comprise a series of wire coils, each coil extending along said tube and being secured to the adjacent coil.

4. A tube filter, as set forth in claim 2, in which said spacing members comprise a series of wire coils, each coil extending along said tube, alternate coils being wound with right hand and left hand pitches respectively and being interleaved to form securing loops and rods extending through said loops to secure adjacent coils together.

5. A tube filter, as set forth in claim 2, in which said spacing members comprise a series of wire coils, each coil extending along said tube and being secured to the adjacent coil, rods extending through the end coils and pins joining said rods to said block to secure the various coils around said tube.

6. A tube filter, as set forth in claim 2, in which said spacing members comprise a series Yof wire coils, each coil extending along said tube and being secured to the adjacent coil, said coils being triangular in section and disposed with a side facing said fabric and with points engaging said tube.

7. A tube lter, as set forth in claim 6, in which said sides are arcuate in form and arranged to form a substantially continuous cylindrical supporting surface for said fabric.

8. A tube filter, as set forth in claim 1, in which a vent is formed in said tube at the upper end of said chamber to prevent trapping of air therein.

9. A tube filter comprising a tube adapted to be immersed in the liquid to be "filtered, a block extending longitudinally along one side only of said tube and having an outer surface spaced from the surface of said tube, a filter fabric surrounding said tube with side edges overlapping said block, a sealing gasket disposed along .said block over said side edges and sealing the overlapped portions, a clamping strip disposed over said gasket, and memberssecuring said clamping strip to hold said gasket in pressure engagement with said fabric edges to secure and seal the same, spacing members disposed between said tube and fabric and extending around said tube to space the fabric therefrom and form an annular liquid vreceiving chamber, and an opening in the bottom of the tube or the passage of liquid between said chamber and the inside of said tube, said' spacing members comprising a series of wire coils each coil extending longitudinaly along said tube and being triangular in section with a side facing said'fabric and a point engaging said tube, said sides being arcuate in form and arranged to form a substantially continuous cylindrical supporting surface for said fabric.

EDMUND G. SMITH. OTELL M. COCCHIARELLA.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 169,591 Great Britain Oct. 6, 1921, 

